Green Springs Earthcache EarthCache

The geological definition of a spring is a natural flow of water from the ground or from rocks, representing an outlet for the water that has accumulated in permeable rock strata underground. Some of the water that falls as rain soaks into the soil and is drawn downward by gravity to a depth where all openings and pore spaces in the rock or soil have become completely saturated with water. This region is called the zone of saturation, and the water it holds, groundwater. The upper surface of the zone of saturation is called the water table. Above the water table lies the zone of aeration, where the pore spaces in the soil are quite dry and are filled with air. When the upper surface of the groundwater (water table) intersects a sloping land surface, a spring appears. The occurrence of springs is closely related to the geology of an area. If an impervious layer of rock, such as a clay deposit, underlies a layer of saturated soil or rock, then a line of springs will tend to appear on a slope where the clay layer outcrops. Springs can be a valuable water resource, and improvement in flow can often be accomplished simply by driving a pipe into the ground at the point where water seeps from the ground.

Springs are classified in several ways. Two general types of springs are Artesian and Gravity.
An ARTESIAN spring occurs when the groundwater, under pressure, finds its way to the land surface.

An artesian spring flows because the pressure in the aquifer (water bearing soil or rock), which is covered by a confining layer (clay or other impervious material), is greater than atmospheric pressure at the land. A spring is formed when the water reaches the surface through a fracture or porous layer. These types of springs usually occur along faults (a fracture in the earth), or in areas of great topographic relief such as cliffs or valleys.

A GRAVITY spring is formed by water soaking into the ground until the water encounters a confining layer that will not let the water seep further down. The water then flows across the top of the confining layer until it reaches the ground surface. Examples of gravity springs are springs found in hillsides or cliffs.

Springs are also classified by the volume of the water they discharge. The scale for spring flow is as follows:

To log this this Earthcache:

1. Take a photo at the spring and include your GPS in the photo. You may include yourself in the photo as well, but that is not required. Post your picture with your log.
2. Do you think this is an artesian spring or a gravity spring?
3. What was the flow rate of the spring when you visited in liters/second (L/s). To determine this measure the time it takes to fill your container. Divide the volume of your container (in liters) by the time it took to fill the container (in seconds). You might want to try this several times and use an average time for your calculation.
   
4. Given the flow that you measured, what is the magnitude of this spring?
5. An average sized above-ground backyard swimming pool holds roughly 50,000 L. Based on the flow rate you measured, how many days would it take this spring to discharge 50,000 L of water?
   
   Now to put these flows into perspective consider this: A 1st magnitude spring could fill that same 50,000 L swimming pool in under 18 seconds! I could not find any reference indicating if there are any 1st magnitude springs in Canada, but there are several in the US, and most of those are in Florida.